This invention relates to the art of slitting paper webs, and is more particularly concerned with a new and improved arrangement wherein the lower slitter blades are power driven in a manner to permit a paper web to be slit into narrow strips.
Rotary slitters have heretofore provided for the horizontal adjustment of the upper and lower blades which are adapted for separating a paper web into strips of selected widths. Where the lower blades or slitter bands have been motor driven, it has been customary to mount the slitter bands directly on the ends of driving motor shafts which are horizontally parallel to the path of movement of the web. An example in the prior art of such an arrangement is found in U.S. Pat. No. 3,176,566. However, there are two major problems with such an arrangement. One such problem resides in that the strip width is limited to dimensions no narrower than the combined length of motor and blade. A second problem resides in that the precision with which the blade rotates is limited to the accuracy obtainable in the shaft and bearings of the motor, and the usual inaccuracies in these components results in poor quality slitting, blade damage, or both.
In more recent times the slit or strip width problem has been addressed through the application of so-called "pancake" type motors having a very short axial length relative to their diameter. However, the problems of shaft and bearing runout persist and may even be more severe.